Enhanced photoelectric performance in Cu–Bi double halide perovskite single crystals

Abstract

Bi-based halide perovskites, with much lower toxicity than Pb-based perovskites, have triggered enormous interest in optoelectronic applications. However, most Bi-based perovskites have low-dimensional crystalline structures which may have potential negative effects on carrier transport. Herein, zero-dimensional (CHDA)BiI₅·3H₂O is transformed into two-dimensional double perovskite (CHDA)₂CuBiI₈·0.5H₂O through Cu⁺ introduction engineering, which shows increased orbital overlap and improved electronic band structure dispersion compared with the former. Notably, a 104-fold enhancement in photoresponse on–off ratio is observed for the (CHDA)₂CuBiI₈·0.5H₂O SC photodetector. This advancement not only enhances our understanding of the intricate relationship between crystal structure and charge transport behavior in Bi-based perovskites but also paves the way for highly efficient and environmentally friendly optoelectronic device development.